The present invention relates to neurogenesis inducing genes.
The early process of vertebrate neurogenesis is divided into several basic processes, such as differentiation into the neural plate (neural induction) and formation and maturation of the neural network from the ectoderm. This early process includes occurrence of neural precursor cells, pattern formation of the nervous system, and proliferation and differentiation of neural precursor cells.
It is known that the early neurogenesis of Xenopus laevis is induced by blockade of BMP4 (i.e., Bone Morphogenetic Protein 4) signals by noggin, chordin, etc. (Sasai et al., Nature, 376:333 [1995]; and Mizuseki et al., Development 125:579-587 [1998]). BMP4 is a factor which induces the ectoderm into epidermal cells. When BMP4 is activated, cells differentiate into the epidermis. Proneural genes (e.g., Neurogenin, NeuroD, XASH-3, XATH-3) which are involved in the control of neural induction (i.e., Neurogenesis, neural differentiation) and in the coding for basic helix-loop-helix(bHLH) transcription factors are also known. However, the factors involved in the blockade of BMP4 signals to proneural genes are still unknown.
Understanding the molecular basis of higher brain functions is important, not only to elucidate the universal principle of these processes, but also in the development of new therapeutic methods for treatment of diseases involving brain functions (i.e., neurogenesis).
The present invention provides neurogenesis inducing proteins, genes coding for the proteins; recombinant vectors comprising the genes, transformants comprising the vectors, an antibodies against the proteins; and therapeutic agents for nervous diseases.
In one embodiment, the present invention relates to a recombinant protein having a protein comprising at least a portion of the amino acid sequence set forth in SEQ ID NO:2. In some embodiments, the present invention provides a protein which consists of the amino acid sequence shown in SEQ ID NO: 2 having a deletion, substitution, or addition of at least one amino acid and which has neurogenesis inducing activity. In another embodiment, the present invention relates to a neurogenesis inducing gene encoding for a protein comprising at least a portion of the amino acid sequence set forth in SEQ ID NO:2 or a neurogenesis inducing gene encoding for a protein comprising at least a portion of the amino acid sequence set forth in SEQ ID NO:2 having a deletion, substitution, or addition of at least one amino acid and which has neurogenesis inducing activity. The present invention also relates to a gene which hybridizes with the neurogenesis inducing gene encoding for a protein comprising at least a portion of the amino acid sequence set forth in SEQ ID NO:2.
In another embodiment, the present invention relates to a gene comprising a DNA sequence having at least a portion of the nucleotide sequence set forth in SEQ ID NO: 1. The present invention also relates to a DNA which hybridizes with a DNA having at least a portion of the nucleotide sequence set forth in SEQ ID NO:1, and which codes for a protein having neurogenesis inducing activity.
In another embodiment, the present invention relates to an isolated nucleic acid encoding a protein having at least a portion of the amino acid sequence selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 42 and in SEQ ID NO: 44. In one embodiment, the nucleic acid comprises a nucleotide sequence having at least a portion of the sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 41, and SEQ ID NO: 43. In preferred embodiments, the present invention provides a nucleic acid encoding a neurogenesis inducing gene (e.g., early neurogenesis inducing gene). In particular, the present invention provides a nucleic acid encoding a gene selected from the group consisting of Zic1, Zic 2, and Zic3 genes. In one embodiment, the gene is a Xenopus gene.
The present invention further relates to a nucleic acid capable of hybridizing to a nucleic acid comprising a nucleotide sequence having at least a portion of the sequence selected from the group consisting of SEQ ID NO:1, SEQ ID NO: 41, and SEQ ID NO: 43. In a preferred embodiment, the nucleic acid capable of hybridizing under stringent conditions.
In yet another embodiment, the present invention also relates to recombinant vectors comprising at least a portion of genes described above. The present invention further relates to transformants (e.g., a host cell) comprising the recombinant vectors of the present invention.
The present invention also relates to compositions comprising a protein having at least a portion of the amino acid sequence selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 42, and SEQ ID NO: 44. In one embodiment, the protein is selected from the group consisting of Zic1, Zic2, and Zic3 proteins. In another embodiment, the protein is a Xenopus protein. In yet another embodiment, the protein is a recombinant protein.
The present invention also provides antibodies against the above described proteins. In particular, the present invention relates to a purified antibody specific to a protein having at least a portion of the amino acid sequence selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 42, and SEQ ID NO: 44. The present invention further provides therapeutic agents for nervous diseases associated with the above proteins (e.g., in the presence or absence of the proteins). In preferred embodiments, the present invention relates to therapeutic agents or agents for gene therapy of nervous diseases including, but not limited to Alzheimer""s disease, amyotrophic lateral sclerosis, spinocerebellar degeneration, Parkinson""s disease and cerebral ischemia, although it is not intended that the present invention be limited to therapeutic agents related to these diseases.
Furthermore, the present invention relates to methods for producing a neurogenesis inducing protein, comprising, for example, the steps of culturing a transformant comprising a recombinant vector discussed above and recovering the neurogenesis inducing protein from the resultant culture. In one embodiment, the methods of the present invention comprises the steps of: a) providing a composition comprising a recombinant vector, wherein the recombinant vector comprises a nucleic acid having at least a portion of the sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 41 and SEQ ID NO: 43, and a host cell; b) transforming the recombinant vector into the host cell to produce a transformant; and c) culturing the transformant to produce a neurogenesis inducing protein. In one embodiment, the methods of the present invention further comprises the step of d) isolating the neurogenesis inducing protein. In preferred embodiments, the neurogenesis inducing protein is an early neurogenesis inducing protein.
Further, the present invention relates to methods for gene therapy, comprising the steps of: a) providing i) a subject, and ii) a composition comprising a nucleic acid having at least a portion of the sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 41 and SEQ ID NO: 43; and b) delivery the composition to the subject. In preferred embodiments, the subject suffers from a disease selected from the group consisting of Alzheimer""s disease, amyotrophic lateral sclerosis, spinocerebellar degeneration, Parkinson""s disease and cerebral ischemia.